Action Points

Explain to interested patients that multidrug-resistant pathogens are a growing problem both in hospitals and in the community and that methicillin-resistant Staphylococcus aureus is seen as one of the greatest threats.

Note that this study found that when the S. aureus colonizes the intestines, it increases the possibility of contamination on a patient's skin and the surrounding environment.

CLEVELAND, Sept. 13 -- Staphylococcus aureus in the contents of the bedpan increases the risk that the bacteria will contaminate hospital bedrails, as well as skin and other environmental surfaces, researchers here said.

The nose is usually considered the primary site for S. aureus colonization, but patients who also had the bacteria in their stool were more likely to spread contamination, according to Curtis Donskey, M.D., and colleagues from the Cleveland Veterans Affairs Medical Center.

Also, patients with the bacteria in their stool -- whether or not their noses were colonized -- were significantly more likely to have S. aureus infections (P=0.02), the researchers reported online in BMC Infectious Diseases.

The findings come from a six-month prospective study of 71 men who were admitted to the VA Center for at least three days, the researchers said.

Of the 71 patients:

32 (45.1%) were not colonized in either the nose or intestines.

23 (32.4%) tested positive in both the nose and stool samples.

13 (18.3%) carried the bacteria only in their noses.

And three (or 4.2%) carried the bacteria only in their stool.

Of the 39 patients with S. aureus, 76.9% had methicillin-resistant isolates.

The researchers compared the characteristics of patients with the bacteria in the stool (whether or not the nose was colonized), those with bacteria in the nose only, and those who were not colonized.

The only significant difference they found was that 30.8% of patients with the bacteria in the stool developed an S. aureus infection, compared with 15.4% of those with nasal colonization only and 3.1% of those with colonies in neither area. The differences were significant at P=0.02.

The infections included bacteremia in five patients, empyema in one patient, pneumonia in three, and wound infection in two.

To test for the presence of contamination, an investigator first washed his or her hands with a 62.5% alcohol hand rub and placed one hand onto a mannitol salt agar plate to make sure no S. aureus were present.

The same hand was then used sequentially to touch the patient's bedrail, bedside table, groin, and axilla -- each for five seconds -- before being placed on a second agar plate.

Analysis showed:

Skin and environmental cultures were positive for S. aureus significantly more often (at P<0.001) for patients with the bacteria in the nose and intestines or the nose only than for patients who were negative in both sites.

Investigators were significantly more likely to acquire S. aureus on their hands after contacting skin and environmental surfaces of these patients (at P<0.001).

Patients with both nasal and intestinal colonization were significantly more likely than those with nasal colonization only to have positive skin cultures (at P=0.001).

The researchers noted that the study only included men with a hospital stay of three or more days, which may limit the generalizability of the finding.

Also, they said, 15 of the 26 patients with intestinal S. aureus colonization also had diarrhea or fecal incontinence during the study, which is likely to have contributed to contamination.

Nevertheless, they said, "because staphylococci on skin may contaminate devices or wounds and be acquired on hands, our data provide support for the hypothesis that colonization of the intestinal tract may facilitate S. aureus infections and nosocomial transmission."

The research was supported by the Department of Veterans Affairs. The authors said they had no competing interests.

Reviewed by Robert Jasmer, MD Associate Clinical Professor of Medicine, University of California, San Francisco

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